But up until now, few people have done much to help the third “B” of beneficial wildlife — bees and other pollinating insects.

Actually, we’ve done a pretty good job at killing off pollinators by rampant spraying, reducing plant diversity to lawn and a few common shrubs, and teaching kids to dread anything that buzzes.

That’s starting to change as bee populations nose-dive enough to threaten the pollination of everything from farm crops to orchards to backyard tomatoes.

One local effort is a new program developed by Penn State Master Gardeners. The program encourages home gardeners to take steps toward providing safe havens for struggling pollinators.

Dubbed “Pollinator Friendly Gardens,” the program cites gardeners who are taking four key steps:

1. Providing throughout the season nectar and pollen sources, as well as host plants for butterfly and insect larvae. Gardens must include at least four kinds of native trees and shrubs and at least six different kinds of native perennial flowers. 2. Providing water sources, such as bird baths, puddling areas, a water garden or pond, a stream or spring. 3. Providing shelter for pollinators to nest and overwinter, such as rock piles, stone walls, dead wood or bee boxes. 4. Protecting pollinator habits, including eliminating invasive plants that choke out native plants and scrapping pesticides (or switching to less toxic oils and soaps).

So far, 41 Pennsylvania gardeners have applied for and received the certification.

Part of the problem is the amount of species-rich land that’s been replaced by asphalt, concrete and nearly sterile yards of pesticide-treated lawns and meatball foundation shrubs.

“Without blooming plants to serve as food sources, bees have to fly miles for food and pollen,” says Ginger Pryor, Penn State’s Master Gardener coordinator. “Hives under that strain probably won’t survive through the year.”

Why should we care?

Because even though people might not like the idea of bugs and stinging things flying around, they perform a service critical to human life.

That would be transferring pollen from one flower to another, which is how plants reproduce and create the nuts and fruits that we eat.

“Most of our flowering plants need an intermediary,” says Mace Vaughan, the pollinator program director for the Xerces Society (named after a blue butterfly that’s now extinct).

He says more than 70 percent of plants need insects to move pollen and that one in every three bites of food we eat is courtesy of insect pollination. Even our meat and milk trace back to insects that pollinate the corn and other feed for beef cattle and cows.

In the home garden, plants dependent on insect pollinators include tomatoes, squash, cucumbers, strawberries and blueberries, as well as ornamentals such as hollies, crabapples and willows.

Butterflies do some pollinating. Assorted flies, soldier beetles and wasps are excellent, too.

But the king of pollination is the bee.

“When it comes down to it,” says Vaughan, “bees are the pollinators we really want to put our attention on.”

That includes the workhorse European honeybee plus nearly 4,000 species of native U.S. bees, including sweat bees, leaf-cutter bees, long-horned bees, mud bees, carpenter bees and the familiar bumblebee.

Vaughan says populations of honeybees are off by 50 percent since 1950, primarily due to disease, loss of habitat, increased use of insecticides and the recent Colony Collapse Disorder.

Home gardeners can do much to counteract the carnage.

“Gardens are very important as a food source for bees,” Vaughan says. “They need to have pollen and nectar all the way from the willows and redbuds of spring to the goldenrods and asters in fall.”

The more diversity, the better.

“As many plants as you can get out there as possible will help pollinators,” Vaughan says. “At least 15 to 25 different plant species is good. And clustering flowers is important. Bees are much better able to find plants when there are patches 3 or 4 feet around. It’s like a billboard effect. It attracts their attention more.”

Evan Jenkins, a Master Gardener from Hampden Twp., is one of the first in the Harrisburg area to earn a Pollinator Friendly Garden certification, and he’s sold on the difference even one garden can make.

All sorts of life have zeroed in on his Conodoguinet Creek-side landscape.

“I’ve seen 87 different kinds of birds in my yard,” he says. “This attracts more than just bees. It helps all kinds of pollinators.”

And no, he doesn’t get stung.

Neither does Maryann Skubecz, another Master Gardener from Hampden Twp. whose yard was fifth in the state to become a Pollinator Friendly Garden.

“Honeybees are actually quite gentle,” she says.

Skubecz laid out her gardens of native shrubs and perennials in curving beds divided by lawn for a look that’s a blend of natural and tamed.

“Being a Master Gardener taught me a lot about the interaction between nature and gardens,” she says. “That’s what motivated me to plant more natives.”

She adds that pollinator gardens are “important because habitats are being destroyed, and this is something that a homeowner can do to help.”